My Bride is a Mermaid OVA(2008)

Seto no Hanayome OVA

The OVAs are new stand alone shorts with characters from the series and introduces two new ones. It is now the third year of school, San and Luna's dads are still being over protective. All the while Nagasumi has his hands full trying to keep everyone around him under control and rescuing damsels in distress.

(Source: Anime News Network)